Three blocks of masses `m_(1),m_(2)`and `m_(3)` are connected by massless strings as shown on a frictionless table. They are pulled with a force `T_(3)=40N`. If `m_(1)=10kg,m_(2)=6kg` and `m_(3)=4kg` the tension `T_(2)` will be

Options

A. 20 N
B. 40 N
C. 10 N
D. 32 N

Answer

D

Explanation

(d) Acceleration of system
`a=(T_(3))/(m_(1)+m_(2)+m_(3))=(40)/(10+6+4)=2 ms^(-2)`
Equation of motion of `m_(3)` is
`T_(3)-T_(2)=m_(3)a`
`therefore T_(2)=T_(3)-m_(3)a=40-4xx2=32 N`